The efficiency of work for identifying reference points included in photographed images is improved. A survey data processing device includes a data receiving unit 103 that receives data of two still images, an operation information receiving unit 104 that receives a selection of reference points among multiple reference points which are included in both of the two still images and have known location information, an exterior orientation parameter calculating unit 106 that calculates exterior orientation parameters of a camera, a coordinate integrating unit 110 for obtaining an integrated coordinate system for describing both the locations of an unselected reference point and the camera, a back-projected image generating unit 111 for generating a back-projected image by back-projecting the unselected reference point in the integrated coordinate system, and a target position estimating unit 112 that estimates a position of the unselected reference point in a still image.